This invention is related to a two-part milling tool holder which includes a body adapted to be mounted on a milling tool base. A replaceable head for supporting a pair of indexable inserts has a shank received in an opening in the body. The head can be replaced with another head of the same or a different style.
Milling tool inserts are commonly mounted on the end of an elongated tool holder. It is desirable in some cutting situations to use one type of insert for heavy milling and then another insert for cutting a radius or the like. Occasionally, the cutter head becomes damaged or worn. Commercially available heads generally must either be scrapped or repaired. Most of the expense in making the holder is in the body of the holder. Further, replacing a complete toll holder is time consuming.
Prior art related to tool holders such as for milling inserts may be found in my U.S. Pat. Nos. 5,468,102 issued Nov. 21, 1995 for xe2x80x9cMilling Tool Holderxe2x80x9d; and 6,299,394 issued Oct. 9, 2001 for xe2x80x9cMilling Tool Holderxe2x80x9d.
The broad purpose of the present invention is to provide an improved milling tool holder of the type in which a body adapted to be supported on a milling machine base, is connected to a head that supports a pair of indexable inserts. The head has a shank received in a bore in the body.
A pair of threaded fasteners mounted on the body have their inner ends engaging the shank to cam a shoulder on the head toward a shoulder on the body.
The arrangement is such that the user can readily exchange the head whenever it has become damaged, worn, or needs to be exchanged to accommodate a head having a different cutting configuration.
Although the fasteners prevent the shank from rotating with respect to the body, my prior patent disclosed additional means for preventing such rotation. My U.S. Pat. No. 5,468,102 used a pin in the shank-receiving hole, which was received in the slot in the end of the shank when it was inserted in the hole.
The present invention discloses an arrangement that accommodates a heavier torque required by high speed machines for a heavier cut. In this case, the body has a shoulder around the shank-receiving hole. The tool has a shoulder around the shank that seats on the shoulder on the body. One of the channels has a pair of channels aligned along an axis that passes through. the center of the shank-receiving hole. The other shoulder has a pair channels so that the two shoulders combine to form a pair of cylindrical openings.
A cylindrical pin or key is mounted in each cylindrical opening. Each pin is attached to a channel in one of the shoulders.
When the tool shoulder is mounted on the body shoulder in face-to-face contact, the pins prevent the tool from rotating with respect to the body, and increase the torque transmitting properties of the tool holder. This provides a safety feature in the event that the two threaded fasteners should fail to prevent the tool from rotating with respect to the body.
A single pin embodiment is also disclosed. Each shoulder has a single channel. When the head is mounted on the body, the pin attached to one of the shoulders is received in the channel in the other shoulder. This arrangement ensures that the fastener openings in the body are aligned with the openings in the shank.